1. Technical Field
The present invention relates to an image sensor, and more particularly, to an image sensor capable of canceling crosstalk without reduction of a signal to noise ratio (SNR) so that sensitivity may be improved.
2. Description of the Related Art
As the performance of CMOS image sensors (CIS's) are being rapidly improved, CIS devices having beneficial characteristics such as a low power consumption, compact size, and low cost manufacture are being produced. These improved CIS's are replacing charge coupled device (CCD) image sensors. However, as the size of a pixel to capture an image decreases, the following difficulties may be encountered.
For example, as the size of a pixel decreases, the area of a photodiode may decrease as well. Accordingly, even if an on-chip microlens is used, since the amount of light incident on the pixel may decrease, the number of electrons generated by the photodiode may decrease so that a sensitivity may be reduced.
Also, as the size of a pixel decreases, to obtain the highest sensitivity, the distance between adjacent pixels may also need to be decreased. When the distance between the adjacent pixels decreases, the crosstalk between the adjacent pixels may increase. Consequently, as a result, the SNR may be decreased so that color reproduction may thereby be deteriorated.
Moreover, in a conventional RGB Bayer pattern, the transmissivity may be low because each of color filters of the RGB Bayer pattern may absorb incident light. Thus, the sensitivity of a signal may not be high due to a low transmissivity so that it may be difficult to prevent crosstalk.